The present invention relates to a circuit beaker having an interrupter chamber housing composed of plastic and an interrupter arranged in the interrupter chamber housing and having a busbar disposed inside an outside wall of the interrupter housing.
European Patent Document EP 0 560 696 B1 describes a circuit breaker featuring a rotary double-break interrupter, the interrupter chamber housing being composed of two housing modules. The interrupter includes two stationary contact members which are each connected to corresponding connecting terminals via loop-shaped busbars, and a two-arm contact member which is rotatable about an axis and which interconnects the two stationary contacts in its closed position. For mounting the stationary contact members in the interrupter chamber housing in this circuit breaker, these stationary contacts members are inserted together with the busbars into corresponding receptacles of the interrupter chamber housing which are intended for this. In this circuit breaker, it is disadvantageous, inter alia, that the heat generated during the normal use of the busbars is transferred to the interrupter chamber housing relatively slowly because the air surrounding the busbar is a very poor heat conductor. Besides, the busbars which are inserted into the receptacles of the interrupter chamber housing require an additional fixation to guarantee a sufficient strength in the region of the connecting terminals.
An object of the present invention is to specify a circuit breaker of the type mentioned at the outset in which the heat generated by the busbars is readily dissipated into the interrupter chamber housing more rapidly than in known comparable circuit breakers. Moreover, an intention is to provide a method for manufacturing a circuit breaker of that kind.
The present invention provides a circuit breaker having an interrupter chamber housing composed of plastic and an interrupter which is arranged in the interrupter chamber housing and which includes at least one stationary contact member which is connected to a corresponding connecting terminal via a busbar, as well as a pivoting or sliding contact member which, in its closed position, can be connected to the stationary contact member. The busbar is arranged inside the outside wall of the interrupter chamber housing, and connected thereto over a large surface in a positive locking and/or force-locking manner. The busbar is injection-molded around with the plastic which forms the outside walls of the interrupter chamber housing. The present invention further provides a method for manufacturing such a circuit breaker wherein the respective busbar and, possibly, a blowout magnet allocated to the busbar, are brought into a mold for manufacturing the interrupter chamber housing as inserts. The manufacture of the interrupter chamber housing is then carried out by injection molding.
According to the present invention, the conductors are not inserted in corresponding receptacles and fixated using additional means subsequent to the manufacture of the interrupter chamber housing as in the known circuit breakers but, instead, are brought into the outside walls of the interrupter chamber housing already during its manufacture and connected thereto over a large surface (that is virtually over the entire surface) in a positive locking and/or force-locking manner. Such a connection between the busbars and the outside walls of the interrupter chamber housing can be effected by manufacturing the respective interrupter chamber housing by injection molding, the busbars being inserted into the corresponding mold prior to injection molding.
In the case of loop-shaped busbars having blowout magnets arranged between the legs of the busbars (cf., for example, European Patent Document EP 0 560 696 B1 mentioned at the outset), the blowout magnets can also be fixated in the corresponding mold together with the busbars and subsequently molded into the side walls of the interrupter chamber housing during its manufacture. In this manner, both a stable fixation of the respective blowout magnet within the interrupter chamber housing and the required insulation of the respective blowout magnet against the corresponding busbar is achieved in a simple manner.
The circuit breaker according to the present invention not only has the advantage that a good heat transfer takes place from the heated busbars into the interrupter chamber housing surrounding them but also guarantees a high strength of the busbars in the region of the connecting terminals and in the region of the contacts which are subject to high dynamic loads.
A further advantage of the busbars, which are imbedded, such as by being injection-molded around, consists in the mechanically highly firm fixation of the rails in the housing, a later change of the positions of the contacts being ruled out.